'\"macro stdmacro
.\"
.\" Copyright (c) 2008 Aconex.  All Rights Reserved.
.\"
.\" This program is free software; you can redistribute it and/or modify it
.\" under the terms of the GNU General Public License as published by the
.\" Free Software Foundation; either version 2 of the License, or (at your
.\" option) any later version.
.\"
.\" This program is distributed in the hope that it will be useful, but
.\" WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
.\" or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
.\" for more details.
.\"
.\"
.TH PMDAMEMCACHE 1 "PCP" "Performance Co-Pilot"
.SH NAME
\f3pmdamemcache\f1 \- memcached performance metrics domain agent (PMDA)
.SH DESCRIPTION
This \s-1PMDA\s0 extracts performance data from memcached, a distributed
memory caching daemon commonly used to improve web serving performance.
A farm of memcached processes over multiple servers can be utilised by a single
web application, increasing the total available object cache size, and
decreasing the database load associated with smaller cache sizes.  This
system is described in detail at
.BR http://www.danga.com/memcached .
.SH INSTALLATION
Configure \fBpmdamemcache\fR to extract the values from set of hosts
used in the memcache farm.  These hosts can be listed in the
\&\f(CW$PCP_PMDAS_DIR\fR/memcache/memcache.conf file, in the format (i.e.
Perl array) described at the top of pmdamemcache.pl.  A custom
refresh rate can also be configured using this mechanism.
.PP
.ft CW
.nf
.in +0.5i
# cd $PCP_PMDAS_DIR/memcache
# [ edit memcache.conf ]
.in
.fi
.ft 1
.PP
Once this is setup, you can access the names and values for the
memcache performance metrics by doing the following as root:
.PP
.ft CW
.nf
.in +0.5i
# cd $PCP_PMDAS_DIR/memcache
# ./Install
.in
.fi
.ft 1
.PP
If you want to undo the installation, do the following as root:
.PP
.ft CW
.nf
.in +0.5i
# cd $PCP_PMDAS_DIR/memcache
# ./Remove
.in
.fi
.ft 1
.PP
\fBpmdamemcache\fR is launched by \fIpmcd\fR(1) and should never be executed
directly. The Install and Remove scripts notify \fIpmcd\fR(1) when the
agent is installed or removed.
.SH FILES
.IP "\fB$PCP_PMDAS_DIR/memcache/memcache.conf\fR" 4
optional configuration file listing monitored memcache instances
.IP "\fB$PCP_PMDAS_DIR/memcache/Install\fR" 4
installation script for the \fBpmdamemcache\fR agent
.IP "\fB$PCP_PMDAS_DIR/memcache/Remove\fR" 4
undo installation script for the \fBpmdamemcache\fR agent
.IP "\fB$PCP_LOG_DIR/pmcd/memcache.log\fR" 4
default log file for error messages from \fBpmdamemcache\fR
.SH PCP ENVIRONMENT
Environment variables with the prefix \fBPCP_\fR are used to parameterize
the file and directory names used by \fBPCP\fR. On each installation, the
file \fB/etc/pcp.conf\fR contains the local values for these variables.
The \fB$PCP_CONF\fR variable may be used to specify an alternative
configuration file, as described in \fIpcp.conf\fR(5).
.SH SEE ALSO
.BR PCPIntro (1)
and
.BR pmcd (1).
